This invention relates to a teaching aid for use in understanding or visualizing characteristics of a geometric figure.
In teaching geometric figures such as cones or pyramids, it is often necessary to calculate certain dimensions of the geometric figures in order to arrive at a solution to a problem. For example, in calculating the surface area of a side of a pyramid, it is necessary to first solve for the slant height of the pyramid given other dimensions or angles of the pyramid. It has been found that students have difficulty visualizing such dimensions which are not visible from a two-dimensional drawing or three-dimensional representation of the geometric figure. This difficulty also stands in the way of the student solving such a problem.
It is an object of the present invention to provide a teaching aid for geometric figures in order to assist students in visualizing various characteristics or dimensions of a geometric figure. It is a further object of the invention to provide such an aid which can be adapted for use with geometric figures of various shapes. A still further object of the invention is to provide such an aid which facilitates application of indicia by an instructor pertaining to various characteristics or dimensions of the geometric figure. Yet another object of the invention is to provide such an aid which is relatively simple in its construction and yet which greatly enhances visualization or understanding of various aspects of a geometric figure.
In accordance with the invention, a geometric figure teaching aid includes a base member, a rod and at least one side member. The base member defines an outer peripheral edge having a shape corresponding to the shape of the base of a geometric figure, and preferably includes a series of edges which intersect at corners. The rod has a first end interconnected with the base member and terminates at a second end spaced from the first end. The spacing of the second end of the rod from the base member corresponds to the height of the geometric figure. The side member extends from an edge of the base member to the second end of the rod. Preferably, a side member extends from each corner of the base member to the second end of the rod, to define the corners between adjacent sides of the geometric figure. In addition, a side member preferably extends between the second end of the rod and an edge of the side member between an adjacent pair of side members defining corners of the geometric figure. The base member includes at least one line which extends between the first end of the rod and an edge of the base member, to indicate a dimension corresponding to a dimension of the base of the geometric figure. In a preferred form, the base member is formed of a piece of translucent material defining a top surface and a bottom surface. The rod extends from the top surface of the translucent base member, and the line is preferably provided on the bottom surface of the translucent base member. A backing member, such as a backer sheet, may be applied to the bottom surface of the base member so as to enhance visibility of the line. Alternatively, the backer sheet may be eliminated so as to enable the base member of the geometric figure to be useable on an overhead projector or the like. The line may be etched into the bottom surface of the translucent base member, and the top surface of the base member is adapted to receive indicia pertaining to the dimension or characteristic of the geometric figure corresponding to the line on the base member.
In accordance with another aspect of the invention, at least one of the side members carries a clip member for releasably engaging a label for indicating a characteristic of the side member. For example, the label may carry a value indicating a given dimension of the side member, or nomenclature identifying the side member, or a mathematical expression pertaining to the side member. In a preferred form, the side member is in the form of a string or cord extending from the second end of the rod to an edge of the base member, and the clip member is in the form of an alligator clip attached to the string or cord.
The various aspects of the invention may be employed independently of each other, or may be combined in a geometric figure teaching aid incorporating numerous advantageous and greatly facilitating understanding of various aspects of a geometric figure.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.